WHITLOCK, BARBARA A.*, KENNETH G. KAROL, AND WILLIAM S. ALVERSON. Harvard University Herbaria, Cambridge, MA 02138; Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742; Department of Botany, The Field Museum, Chicago, IL 60605. - Chloroplast DNA sequences confirm the placement of Oceanopapaver within the Grewioideae (Tiliaceae or Malvaceae s.l.).
The monotypic genus Oceanopapaver is an endemic shrub found
growing on serpentine soils in New Caledonia. Since its description
in 1932, O. neocaledonicum Guillaumin has been placed in at
least five families, including Capparaceae, Cistaceae,
Oceanopapaveraceae, Papaveraceae and Tiliaceae. The chloroplast genes
rbcL and ndhF were sequenced and phylogenetic analyses performed to
clarify the taxonomic placement of this genus. The results strongly
support the inclusion of Oceanopapaver in a clade of former
Tiliaceae, the Grewioideae (Malvaceae s.l.). Within Grewioideae,
Oceanopapaver forms a well-supported clade with representatives
of the pantropical genus Corchorus and the endemic Malagasy
genus Pseudocorchorus. This placement was anticipated by Tirel
et al. (1996) who, based on morphology, reduced Oceanopapaver
to a synonym of Corchorus. Morphological characters consistent
with this placement include stellate indumentum, mucilage canals,
valvate sepals with stellate hairs on the adaxial surface, and pollen
morphology.
Key words: Malvaceae, Malvales, Oceanopapaver , Tiliaceae